1. Field of the Invention
This invention relates to autofocus device and method and a program product therefor, which are used in an imaging apparatus such as a video camera and a digital still camera.
2. Description of Related Art
The imaging apparatus such as a video camera and a digital still camera has been equipped with any autofocus mechanism that automatically focuses on a subject. The autofocus mechanism adds frequency components of an image signal in a particular region that is provided in an imaging frame (finder's view) to calculate a focus evaluation value thereof and drives a focus lens so that the maximum focus evaluation value can be given (see Japanese Patent Application Publication No. H10-213736). Thus, if imaging after such the particular region is set on a center of the imaging frame and a composition of the imaging frame is fixed to put the subject on the center of the imaging frame, the subject can be automatically focused when a position of a focal point of the focus lens meets an in-focus position. When starting a focusing operation such that the focus lens is driven to meet the position of the focal point of the focus lens to the in-focus position, a wobbling lens wobbles in order to prevent the focus lens from being driven in a reverse direction against a direction in which an in-focus position stays, thereby determining a driving direction of the focus lens based on any alteration in the focus evaluation value at this wobbling.